1, 3-Cycloadditions to Highly Substituted, Strained Double Bonds: Spiro ?-lactams from ?-methylidene-?-lactams by reactions with diphenylnitrilimine, acetonitrile oxide, nitrones, and diazomethane
作者:Arthur Strauss、Hans-Hartwig Otto
DOI:10.1002/hlca.19970800606
日期:1997.9.22
Substituted dihydropyrazole-spiro-β-lactams and isoxazolidine-spiro-β-lactam derivatives are regio- and stereoselectively prepared by 1, 3-cydoadditions between substituted α-methylidene-β-lactams and diazomethane, nitrones, or the in-situ-prepared dipoles ‘diphenylnitrilimine’ and acetonitrile oxide. These reactions represent examples for 1, 3-cycloadditions to the highly substituted, strained double
取代的二氢吡唑-螺-β内酰胺类和异恶唑烷-螺-β内酰胺衍生物是区域选择性和立体选择性地通过取代的α亚甲基β内酰胺类和重氮甲烷,硝酮,或之间1,3- cydoadditions制备在-原位-prepared偶极“二苯基硝胺”和乙腈氧化物。这些反应代表α-亚甲基-β-内酰胺的高度取代的,应变的双键上有1,3-环加成的实例,并且由于所有反应产物都相对不稳定,因此它们需要特殊的实验条件。特别是在溶液中,逆反应是非常有利的。主要通过诸如2D-INEPT,ATP和NOE实验的NMR技术来阐明反应的区域选择性和立体选择性。